Simulations of both soil water content and salinity under tape drip irrigation with different salinity levels of water. Issue 4 (4th July 2017) - Javadzadeh, Firouzeh
Abstract: The purpose of the present research is to evaluate HYDRUS-2D model so as to simulate soil water content and salinity under field conditions. Soil texture is a heterogeneous heavy soil. In this research, drip irrigation (tape) system was applied as a line source with water salinities of 1.279, 2.5, and 5 dS m −1 in three volumes of irrigation water including 10, 15, and 20 l. The observed soil moisture and Electrical conductivity of soil saturated extract (EC e ) values were compared with the simulated values using normalized Root Mean Square Error (nRMSE) and Coefficient of Residual Mass (CRM). Ranges of water content nRMSE were between .91 and 2.07%, and those of CRM were between −.0080 and .0170. For salinity, ranges of CRM for beneath the tape were between −.049 and .097 and between −.065 and .081 for the horizontal distance. Ranges of nRMSE for beneath the tape and the horizontal distance were between 2.79 and 18.49% as well as 3.08 and 20%, respectively. The performance of the model was placed in excellent category to simulate the soil water content; in addition, it was placed in good to excellent classes to simulate soil salinity.